1. Technical Field
The present disclosure relates to a method for manufacturing light emitting chips, and more particularly, to a method for manufacturing light emitting chips having high light emitting efficiency.
2. Description of Related Art
As new type light source, LEDs are widely used in various applications. An LED often includes an LED chip to emit light. A conventional LED chip includes a substrate, and an N-type semiconductor layer, a light-emitting layer and a P-type semiconductor layer sequentially grown on the substrate. The substrate is generally made of sapphire (Al2O3) for providing growing environment to the layers. However, such sapphire substrate has a low heat conductive capability, causing that heat generated by the layers cannot be timely dissipated. Therefore, a new type substrate made of Si is developed. Such Si substrate has a thermal conductivity larger than that of the sapphire substrate so that the heat generated by the layers can be effectively removed.
Nevertheless, such Si substrate also has a problem that it absorbs the light emitted from the light-emitting layer due to the material characteristic thereof. Thus, the light extracting efficiency of the LED chip is limited.
What is needed, therefore, is a method for manufacturing light emitting chips which can overcome the limitations described above.